Thursday, March 12, 2015

Arsenic and Evolution

In South America's Atacama Dessert, the water is rich in arsenic, as much as 20 times the levels considered safe for consumption. So over the 10,000 years people have lived there they have evolved substantial resistance to arsenic. Scientists have recently identified one of the genes responsible, a variant of one called AS3MT that codes for a liver protein.

The entry of humans in to more and more environments in diverse parts of the world, with diverse parasites and poisons, is one of the reasons why our evolution has speeded up so dramatically in the past 100,000 years.

3 comments:

G. Verloren
said...

Out of curiosity, why is it when a bird or a lizard or whatever spreads to a different region and adapts to local conditions, we consider them to be different or at least sub-species; but when humans do it we make no such distinctions?

The findings of recent genetic studies absolutely could be grist for the mill of racists. If evolution over the past 20,000 years has been very rapid -- as all the data suggest --then doesn't that mean Africans, Americans and East Asians are a lot more different than liberals want to admit? The counter to that would be that diversity within our young species -- 200,000 years, vs. 2 million for wolves or lions -- is still not very great, and all the evidence suggests that cultural factors override genetic differences. Chinese Americans are different from white or black Americans, but they are even more different from Chinese people living in China.

I still worry, though, that this new genetic science could lead to a lot of ugliness in the wrong hands, which in turn could lead to strong pressure to repress or deny it. We must take a strong stand that denying the truth is foolish and wrong, and also that our common humanity must override the interesting minor differences between human groups.